According to Engadget's two sources, the shape closely resembles an oval cylinder when closed - a bit like a flask. It certainly sounds, er, different, although not exactly economical with space.

Flask-like Android

When it comes to spec, Engadget has been told it will offer a Tegra 2 SoC, WiFi, 3G and at least one rear-facing camera, although which way is rear-facing may be hard to tell.

The source also said that Sony will be working on the Honeycomb OS to make the most of that dual display; a prototype device apparently showed Gmail running with the inbox shown on one screen and the open message shown on the other.

The two sources aren't exactly enthused by the project, unfortunately; one says that "the whole project is being met with skepticism within Sony." Meanwhile, the other source "calls the S2 an outright "dog."" Ouch.

Europe is set to get the ambitious dual-screen tablet by Christmas, with a UK price of around £590.

And now, to Windows

Meanwhile, Windows fans may be pleased to hear that a VAIO-branded Windows 7 slider tablet is also rumoured to be in Sony's works.

This fared a little better among Engadget's sources, being described as "nice" and similar to the Asus Eee Pad Slider.

The unnamed Windows tablet has a slightly higher target price of $799 (£670) although this is quite likely to rise, apparently.

Both tablets will have a focus on Qriocity, Sony's music and media service, although there's no word on whether or not either or both will be PlayStation Certified.